The Marcasite Confusion
| Marcasite | |
|---|---|
 |
|
| General | |
| Category | |
| Chemical formula | FeS2 |
| Identification | |
| Molar mass | 119.98 |
| Color | Brass Yellow |
| Crystal system | Orthorhombic, Pnnm |
| Cleavage | [010] Indistinct |
| Fracture | Irregular/Uneven |
| Tenacity | Brittle |
| Mohs scale hardness | 6-6.5 |
| Luster | Metallic |
| Streak | Dark-grey to black. |
| Density | 4.875 g/cm3 |
| Ultraviolet fluorescence | None |
Marcasite is the jewellery term given to a form of iron pyrite. Pyrite is the common name for iron sulfide which is generally found in nature in a wide variety of locations. The form of pyrite that is used in jewellery is an angular crystal form whilst true marcasite, although of the same composition, can not be used due to the way it crystalises making it far too brittle to work.
Mineral Pyrite has a metallic lustre that shines beautifully when chiseled with facets. It is brass yellow in colour leading to it being occasionally mistaken for gold and earning it the nickname of ‘fool’s gold’ whilst true marcasite is more of a white yellow.
The name ‘pyrite’ comes from the Greek word ‘pyr’ meaning fire on account of the sparks that are created when the rock is struck. Although the more correct name for the material used in jewellery is pyrite, the name ‘marcasite’ , derived from the Arabic word for pyrite, 'markaschatsa', was adopted many centuries ago and has remained the jewellery term.
The perfect partner for marcasite is silver. Find out why here.
